Thompson & Morgan

Facebook q&a session - November 12th


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Name: Kay Mckenna

Question: Hi Sue, my begonia was hit by frost a couple of weeks ago and I cut the damaged growth off but wonder what I do now. Should I cut all the growth off?


Answer:Hi Kay, I would leave any undamaged growth intact and prepare the plant for over-wintering. All Begonias are sensitive to frost - some types can be over-wintered as dry tubers, whilst others remain evergreen in their containers throughout the winter.
If your variety of begonia is tuberous then stop watering it now and allow the compost to dry out. Alternatively lift it and clean the tubers and lay them somewhere dry and frost-free to allow the foliage to die completely. The dead foliage can then be removed and the tubers stored in containers of dry sand or peat (or even in paper bags) somewhere cool and frost-free. Keep them at a temperature of 5-10C.If your Begonia is not a tuberous variety then simply bring it indoors to a bright, cool and frost-free position (a slightly heated greenhouse or bright windowsill is ideal). Water sparingly as Begonias are susceptible to stem and rhizome rot. You can plant it back outside in late spring after the risk of frost has passed.



Name: Bill Holder

Question: Hi Sue, I have a OSTRICH FERN - Matteuccia and this is first year of having one, I’ve found that all fronds have gone/died and not sure it will grow back, does this usually happen for winter?


Answer: Hi Bill, ostrich ferns (Matteuccia struthiopteris) are indeed deciduous so the leaves dying back are perfectly normal. They are fully hardy so in early spring you should start to see growth at the crown again.



Name: Katrina Jurd

Question: Hi sue, I have two apple trees in my garden and thinking of taking one out, would this mean the remaining apple tree will fail to produce fruit due to pollination? Many thanks


Answer: Hi Katrina, it depends on the varieties of apple you have. Many apples are self-fertile but there are others which require another tree from the same pollination group for pollination to occur and fruit to set. Regardless of whether they are self-fertile you will always get a better fruit set if there is a pollinator growing nearby. If you can give me the names of your apple varieties I may be able to help you further.



Name: Becky Whitehead

Question: Hello need help my bulbs have started sprouting already is this right? I planted in October


Answer: Hi Becky, don’t worry this is perfectly normal particularly if they were planted while the soil was still warm. Many bulbs put on a small amount of growth in the autumn, which is often fairly frost hardy and will over-winter quite happily. At home my Iris bulbs have started sprouting too!



Name: Matthew Eddy

Question: I have new apple trees that are 2 years old. They have black spots and marks on the leaves. What is this please?


Answer: Hi Matthew, it sounds like your tree may have apple scab, which is a common fungal infection on apples and pear trees. It affects both leaves and fruit so it is well worth tackling now. Firstly clear up all leaves that have fallen from the trees and either burn them or dispose of them with household waste as this will prevent the fungus from over-wintering so easily. You’ll also need to spray the tree with a systemic fungicide in the spring, which will be available at all good garden centres. Look out for the active ingredients ‘Difenoconazole’ or ‘Myclobutanil’ on the bottle and follow the manufacturer’s instructions. Also check it is suitable for use on fruit trees. You could also consider pruning out any congested branches to allow good air circulation (the fungus thrives in warm damp conditions). Good luck Matthew, I hope this resolves the problem.



Name: Linda Lund

Question: Greetings from Norway. I just love Dahlias but it is a short season in the garden. Is it possible to move a couple inside and let them grow in the winter??? This year many of my Dahlias did not have flowers before august. In the middle of august we had frost. This year I began with seeds in March but next year I will try to begin in January. I will buy some plant-lights.


Answer: Hi Linda, Dahlias are tuberous plants and naturally become dormant for the winter as the weather gets colder and the days shorten. You could extend their season a little by bringing them into a heated greenhouse and putting them under horticultural lights but they will still require a dormant period. It would be best if you over-winter the tubers by lifting them, brushing off any soil and placing them somewhere frost-free to dry out. Once they are dry store them in containers or paper bags but keep checking them throughout winter for signs of rotting.
In February you can pot up the tubers and start growing them in your heated greenhouse under lights again. This should certainly give them a head start. As soon as the risk of frost has passed in late spring or early summer you can plant them outside. Hopefully as you started growing them so early in the year they will be ready to flower sooner to maximise your short growing season. If you are growing Dahlias from seed then starting them in January may be a good idea - if you have the space!



Name: Toby B. Mann

Question: Hi, just a couple of quickies for tomorrow - Is Rudbeckia "Cherokee Sunset" a perennial or an annual? Next to my Roses it has to be my flower of the year, it's still flowering! Also I've just divided a very mature Helleborus niger (a bit late I know) but I wasn't too sure whether to remove all the leaves, I've taken off the damaged growth and left a couple, should I remove the lot? Thanks


Answer: Hi Toby, Rudbeckia ‘Cherokee Sunset’ is a perennial but may not be reliably hardy in the UK. It may be best to mulch at the base of the plant just in case we get another extreme winter this year. With regards to the Hellebore, it’s natural for them to retain some leaves throughout the year so I wouldn’t remove any more leaves. The plant will need these to produce energy and re-establish itself in its new home.



Name: Pauline Thomas

Question: In June I received 10 small plug plant hardy geraniums (doubles) by mail order. As they developed I noticed they all had grey powdery mildew on the leaves....they have died back now and were potted on...is it worth keeping them or not?


Answer: Hi Pauline, it is definitely worth keeping your geraniums! It sounds as though they were suffering from a fungal infection called mildew. Remove and destroy any old foliage to prevent the spores overwintering and re-infecting your plants next spring. If you notice any powdery mildew on the leaves when they have re-emerged in the spring then spray with a fungicide from your local garden centre (it will say on the bottle whether it is suitable for powdery mildew on ornamental plants).
Powdery mildew thrives in poorly ventilated, humid, damp conditions. Try to keep the plants well ventilated next year and water them from beneath the foliage where possible to reduce the risk of infection.



Name: Victoria Lewis

Question: I have bought the Allium collection and noted that the plant instructions advise to plant the bulbs amongst low growing shrubs to disguise the foliage that dies back before the alliums flower. Can you suggest a plant to grow the alliums alongside please?


Answer: Hi Victoria, you may be better off planting the Alliums amongst herbaceous perennials, rather than shrubs as shrubs can quickly become large and widespread. Perennial grasses would be ideal for growing with Alliums. You could try Stipa tenuissima or a variety of Carex. Hardy Geraniums also make good partners, with their thick clumps of leaves appearing in spring. Sedum spectabile produces thick foliage which would disguise the Allium leaves along with Alchemilla mollis (Lady’s Mantle). Alchemilla mollis has bright green/yellow flowers and makes a superb contrast with purple Alliums. There are many more you could experiment with but I hope this gives you some ideas!



Name: Tony Webster

Question: I have a very ancient laburnum tree, it has lots of straight new growth on it and is top heavy, how and when can I prune it, thanks


Answer: Hi Tony. The best time to prune your laburnum is from late summer to mid winter – so you could tackle it now if you wanted. Laburnum should never be pruned in spring when the sap is rising as they may bleed excessively.
I am not sure where the ‘straight growth’ is growing from but if you notice that it is shooting up from ground level then it is likely that these shoots are suckers from the rootstock. These should be removed. Mature laburnum trees should only really be pruned to shape and the dead or diseased wood removed. Renovation pruning is rarely successful, so if your tree is very old and misshapen then you would be best to remove it and start again. They tend to be a relatively short lived tree but a young new plant will make quick growth.



Name: John Fowell

Question: Hi Sue, could you tell me if there's anything I could have grown in my hanging baskets over winter that's trailing (not ivy)?
Also, could you please identify this climber plant that I discovered a couple of years ago in my garden that goes crazy in the Summer with loads and loads of huge leaves and then dies off in the winter?


Answer: Hi John, the only thing that comes to mind for trailing winter plants, apart from ivy, are trailing pansies such as ‘Friolina’. Although this particular variety won’t be dispatched until the spring, you may find a similar plant in a local garden centre.
With regards to the climber, it looks like some sort of Vitis species (the grape vine family), which are often grown for their foliage. They climb using tendrils, much like sweet peas. As you’ve said they can be very vigorous!
You also mentioned you have many annual plants still in flower – this is quite normal when we have mild autumns. Many of my annuals at home are still flowering too! When the weather becomes colder with prolonged frosts, they will stop flowering and die back.



Name: Roy Roberts

Question:Where can I get seeds of Korean Chrysanthemums?


Answer: Hi Roy, we sell seed for a variety of Korean Chrysanthemum called ‘Fanfare Improved’ which is a hardy herbaceous perennial. I hope this is what you were looking for.